PoE++ (IEEE 802.3bt) pushes up to 90 W down a single cord — enough to power an access point, a PTZ camera or a small switch. The catch is heat: thin conductors in a tight bundle get warm, and warm copper loses margin. Here is how to spec cords that don't cook.
The heat problem
Power loss in a cord is I²R. For a given wattage, thinner wire (higher AWG number) means higher resistance and more heat. Bundle 48 slim cords in a horizontal manager and the temperature rise compounds — TIA guidance (TSB-184-A) caps how much DC resistance you can tolerate before the data link degrades.
AWG is the lever you control
| Conductor | Approx. Ø | Resistance | PoE guidance |
|---|---|---|---|
| 24 AWG | ~6.0 mm | lowest | Best for 60–90 W, long or bundled runs |
| 26 AWG | ~5.0 mm | low | Solid for 90 W with headroom |
| 28 AWG | ~4.0 mm | moderate | Good to ~30 W, keep bundles short |
| 32 AWG | ~3.0 mm | higher | 15–30 W only, de-bundle |
| 34 AWG | ~2.4 mm | highest | PoE-light (≤15 W), shortest patches |
Category and length still matter
- Any category carries PoE — the power travels on the same pairs regardless of Cat rating.
- 10G needs Cat6A+ for the data side; PoE just adds the thermal budget on top.
- Keep high-power runs short and break bundles open where you can — a 0.5 m cord running 90 W is a different animal from a 20 m one.
Rule of thumb: For 60–90 W devices (high-power APs, pan-tilt-zoom cameras, small switches), favor 24/26 AWG — e.g. Cat8 24 AWG or Cat6A 26 AWG. Reserve 32/34 AWG for ≤30 W and short patches.